CN219740189U - Current detection circuit of switching power supply and switching power supply - Google Patents
Current detection circuit of switching power supply and switching power supply Download PDFInfo
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Abstract
The embodiment of the utility model discloses a current detection circuit of a switching power supply and the switching power supply, wherein the current detection circuit comprises an overcurrent detection circuit, a light load detection circuit and a controller, the overcurrent detection circuit is connected with an output port of the switching power supply and is provided with a first reference node, and the first reference node is provided with a first voltage; the light load detection circuit is connected with the overcurrent detection circuit in parallel, is connected with an output port of the switching power supply, and is provided with a second reference node, and the second reference node is provided with a second voltage; the controller is connected with the overcurrent detection circuit and the light load detection circuit, and obtains the first voltage or the second voltage so as to realize automatic switching between the overcurrent detection circuit and the light load detection circuit, so that the current detection circuit can detect larger current and smaller current, and the device is convenient and quick.
Description
Technical Field
The utility model relates to the technical field of switching power supplies, in particular to a current detection circuit of a switching power supply and the switching power supply.
Background
In the related technical field, when a switch power supply is connected with a large load, the switch power supply outputs a large current, and an overcurrent state can exist; when the switch power supply is connected with a smaller load, the switch power supply can output smaller current, and often the current detection circuit can only detect larger current or smaller current, so that inconvenience is caused to detection.
Disclosure of Invention
The embodiment of the utility model provides a current detection circuit of a switching power supply and the switching power supply, which can realize automatic switching between an overcurrent detection circuit and a light load detection circuit according to the current, so as to ensure that the current detection circuit can detect larger current and smaller current.
In a first aspect, an embodiment of the present utility model provides a current detection circuit of a switching power supply, including an overcurrent detection circuit, a light load detection circuit, and a controller, where the overcurrent detection circuit is connected to an output port of the switching power supply and has a first reference node, and the first reference node has a first voltage; the light load detection circuit is connected with the overcurrent detection circuit in parallel, is connected with an output port of the switching power supply, and is provided with a second reference node, and the second reference node is provided with a second voltage; the controller is connected with the overcurrent detection circuit and the light load detection circuit, acquires a first voltage or a second voltage, and controls the overcurrent detection circuit to be in a conducting state and controls the light load detection circuit to be in a cutting-off state when the first voltage is greater than or equal to a preset voltage so as to enable the controller to acquire the first voltage and perform overcurrent detection on the output port; when the first voltage is smaller than the preset voltage, the controller controls the overcurrent detection circuit to be in an off state and controls the light load detection circuit to be in an on state, so that the controller obtains the second voltage and carries out light load detection on the output port; when the second voltage is greater than or equal to the preset voltage, the controller controls the overcurrent detection circuit to be in an on state and controls the light load detection circuit to be in an off state, so that the controller obtains the first voltage and carries out overcurrent detection on the output port.
Based on the above embodiment, when the switching power supply is in the sleep state, the controller controls the overcurrent detection circuit to be in the off state and controls the light load detection circuit to be in the off state; when the switching power supply supplies power to a load, the controller controls the overcurrent detection circuit to be conducted, so that the controller obtains first voltage at a first reference node to carry out overcurrent detection on the output port; when the first voltage is greater than or equal to a preset voltage, the controller controls the overcurrent detection circuit to be kept on, and controls the light load detection circuit to be kept off; when the first voltage acquired by the first reference node is smaller than a preset voltage, the controller controls the overcurrent detection circuit to be turned off, controls the light load detection circuit to be turned on, and acquires the second voltage from the second reference node so as to perform light load detection on the output port; when the second voltage is smaller than the preset voltage, the controller controls the light load detection circuit to be kept on, and controls the overcurrent detection circuit to be kept off; when the second voltage acquired by the controller from the second reference node is greater than or equal to the preset voltage, the controller controls the over-current detection circuit to be turned on, controls the light-load detection circuit to be turned off, and acquires the first voltage from the first reference node so as to perform over-current detection on the output port, so that automatic switching between the over-current detection circuit and the light-load detection circuit can be realized according to the current, and the current detection circuit can detect larger current and smaller current, thereby being convenient and fast.
In a second aspect, an embodiment of the present utility model further provides a switching power supply, including a housing, a circuit board and a current detection circuit, where the circuit board is disposed in the housing, and the current detection circuit is disposed on the circuit board.
When the switching power supply is in a dormant state, the controller controls the overcurrent detection circuit to be in an off state and controls the light load detection circuit to be in an off state; when the switching power supply supplies power to a load, the controller controls the overcurrent detection circuit to be conducted, so that the controller obtains first voltage at a first reference node to carry out overcurrent detection on the output port; when the first voltage is greater than or equal to a preset voltage, the controller controls the overcurrent detection circuit to be kept on, and controls the light load detection circuit to be kept off; when the first voltage acquired by the first reference node is smaller than a preset voltage, the controller controls the overcurrent detection circuit to be turned off, controls the light load detection circuit to be turned on, and acquires the second voltage from the second reference node so as to perform light load detection on the output port; when the second voltage is smaller than the preset voltage, the controller controls the light load detection circuit to be kept on, and controls the overcurrent detection circuit to be kept off; when the second voltage acquired by the controller from the second reference node is greater than or equal to the preset voltage, the controller controls the over-current detection circuit to be turned on, controls the light-load detection circuit to be turned off, and acquires the first voltage from the first reference node so as to perform over-current detection on the output port, so that automatic switching between the over-current detection circuit and the light-load detection circuit can be realized according to the current, and the current detection circuit can detect larger current and smaller current, thereby being convenient and fast.
Drawings
In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are necessary for the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model and that other drawings may be obtained from them without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a current detection circuit connected to an output port according to an embodiment of the present utility model;
FIG. 2 is a schematic diagram of a switching power supply according to an embodiment of the present utility model;
fig. 3 is a schematic diagram of a structure in which a current detection circuit is connected to an output port according to an embodiment of the present utility model.
Reference numerals: 1. a current detection circuit; 11. an overcurrent detection circuit; 11A, a first reference node; q1, a first switching element; r1, a first detection resistor; x1, a first current limiting resistor; 12. a light load detection circuit; 12A, a second reference node; q2, a second switching element; r2, a second detection resistor; x2, a second current limiting resistor; 13. a controller; 2. a switching power supply; 21. a housing; 22. a circuit board; 23. an output port.
Detailed Description
The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.
Referring to fig. 1 and 2, an embodiment of the present utility model provides a current detection circuit 1 of a switching power supply, including an overcurrent detection circuit 11, a light load detection circuit 12, and a controller 13, where the overcurrent detection circuit 11 is connected to an output port 23 of the switching power supply 2 and has a first reference node 11A, and the first reference node 11A has a first voltage; the light load detection circuit 12 is connected in parallel with the overcurrent detection circuit 11, is connected with an output port 23 of the switching power supply 2, and is provided with a second reference node 12A, and the second reference node 12A is provided with a second voltage; the controller 13 is connected with the overcurrent detection circuit 11 and the light load detection circuit 12, and obtains a first voltage or a second voltage, when the first voltage is greater than or equal to a preset voltage, the controller 13 controls the overcurrent detection circuit 11 to be in a conducting state and controls the light load detection circuit 12 to be in an off state, so that the controller 13 obtains the first voltage, and overcurrent detection is performed on the output port 23; when the first voltage is smaller than the preset voltage, the controller 13 controls the overcurrent detection circuit 11 to be in an off state and controls the light load detection circuit 12 to be in an on state, so that the controller 13 obtains the second voltage and performs light load detection on the output port 23; when the second voltage is greater than or equal to the preset voltage, the controller 13 controls the overcurrent detection circuit 11 to be in an on state and controls the light load detection circuit 12 to be in an off state, so that the controller 13 obtains the first voltage and performs overcurrent detection on the output port 23.
The overcurrent detection circuit 11 is used for detecting overcurrent of a larger current when the switch power supply 2 is connected to the larger load and the larger current is output through the output port 23, so that the larger current is prevented from burning out other electronic components or loads in the switch power supply 2, the service life of the switch power supply 2 is prolonged, and the load is prevented from being damaged.
The light load detection circuit 12 is used for detecting the light load of the smaller current when the switching power supply 2 is connected to the smaller load and outputs the smaller current through the output port 23, so that the current detection precision is improved.
The controller 13 may be a controller 13 dedicated to the current detection circuit 1, and the controller 13 is electrically connected to a main controller of the switching power supply 2; in other embodiments, the controller 13 may be an original main controller of the switching power supply 2, and in embodiments of the present utility model, the form of the controller 13 is not specifically limited.
When the switching power supply 2 supplies power to a load through the output port 23, the controller 13 controls the overcurrent detection circuit 11 to be turned on, so that the controller 13 can acquire a first voltage at the first reference node 11A, and when the first voltage is greater than or equal to a preset voltage, the controller 13 controls the overcurrent detection circuit 11 to be kept on and controls the light load detection circuit 12 to be kept off, so that the overcurrent detection can be performed on the output port 23 through the overcurrent detection circuit 11; when the first voltage obtained by the first reference node 11A is smaller than a preset voltage, the controller 13 controls the overcurrent detection circuit 11 to be turned off, controls the light load detection circuit 12 to be turned on, and obtains a second voltage from the second reference node 12A, so that the output port 23 can be subjected to light load detection by the light load detection circuit 12; when the second voltage is less than or equal to the preset voltage, the controller 13 controls the light load detection circuit 12 to be kept on, and controls the overcurrent detection circuit 11 to be kept off; when the second voltage obtained by the controller 13 from the second reference node 12A is greater than or equal to the preset voltage, the controller 13 controls the over-current detection circuit 11 to be turned on, controls the light-load detection circuit 12 to be turned off, and obtains the first voltage from the first reference node 11A, so that the output port 23 can be subjected to over-current detection through the over-current detection circuit 11, and automatic switching between the over-current detection circuit 11 and the light-load detection circuit 12 can be performed according to the voltage of the first reference node 11A and the voltage of the second reference node 12A, so that the same current detection circuit 1 can detect larger current and smaller current, and convenience and quickness are ensured. In addition, when no load is connected to the output port 23, the controller 13 can control the switching power supply 2 to enter a sleep state, and control the overcurrent detection circuit 11 to be in an off state and the light load detection circuit 12 to be in an off state so as to reduce the electric energy loss; when the insertion detection circuit detects that the load is connected to the output port 23, a wake-up signal is sent to the controller 13, so that the switching power supply 2 supplies power to the load through the output port 23, and the controller 13 controls the current detection circuit 1 to perform current detection on the output port 23.
It is understood that the preset voltage may also be a preset voltage interval, and the preset voltage interval has a larger interval endpoint value and a smaller interval endpoint value; when the first voltage obtained by the controller 13 is greater than or equal to the smaller interval endpoint value, the controller 13 controls the overcurrent detection circuit 11 to be kept on, controls the light load detection circuit 12 to be kept off, and continuously obtains the first voltage from the first reference node 11A, so that the output port 23 can be subjected to overcurrent detection through the overcurrent detection circuit 11; when the first voltage obtained by the controller 13 is smaller than the smaller interval endpoint value, the controller 13 controls the overcurrent detection circuit 11 to be turned off, controls the light load detection circuit 12 to be turned on, and obtains the second voltage from the second reference node 12A, so that the output port 23 can be subjected to light load detection through the light load detection circuit 12; when the second voltage obtained by the controller 13 is smaller than the larger interval endpoint value, the controller 13 controls the overcurrent detection circuit 11 to be kept off, controls the light load detection circuit 12 to be kept on, and continues to obtain the second voltage from the second reference node 12A, so that the output port 23 can be subjected to light load detection through the light load detection circuit 12; when the second voltage obtained by the controller 13 is greater than or equal to the larger interval endpoint value, the controller 13 controls the over-current detection circuit 11 to be turned on, controls the light-load detection circuit 12 to be turned off, and obtains the first voltage from the first reference node 11A, so that the over-current detection can be performed on the output port 23 through the over-current detection circuit 11.
In other embodiments, when the switching power supply 2 supplies power to the load through the output port 23, the controller 13 may also control the light load detection circuit 12 to be turned on first, and then keep the light load detection circuit 12 to be turned on and turn off the over-current detection circuit 11, or turn on the over-current detection circuit 11 and turn off the light load detection circuit 12 according to the comparison between the second voltage of the second reference node 12A and the preset voltage, which is not described herein.
Referring to fig. 2 and 3, in a specific embodiment, the overcurrent detecting circuit 11 includes a first switching element Q1 and a first detecting resistor R1, an input end of the first switching element Q1 is connected to the output port 23, and a controlled end of the first switching element Q1 is connected to the controller 13; the first end of the first detection resistor R1 is connected to the output end of the first switching element Q1 through the first reference node 11A, the second end of the first detection resistor R1 is grounded, and the first reference node 11A is connected to the controller 13.
When the switching power supply 2 is in the sleep state, the controller 13 transmits a first control signal to the controlled terminal of the first switching element Q1 to turn off between the input terminal and the output terminal of the first switching element Q1, so that power consumption can be reduced. When the switching power supply 2 supplies power to a load through the output port 23, the controller 13 sends a second control signal to the controlled end of the first switching element Q1, so that the input end and the output end of the first switching element Q1 are conducted, the output port 23 is grounded through the first switching element Q1 and the first detection resistor R1, so that the controller 13 can detect a first voltage at the first reference node 11A, when the first voltage is greater than or equal to a preset voltage, the controller 13 controls the overcurrent detection circuit 11 to keep conducting, and controls the light load detection circuit 12 to keep turning off, so that the controller 13 can continuously acquire the first voltage from the first reference node 11A, and further perform overcurrent detection, so that other electronic components or loads in the switching power supply 2 are prevented from being burnt out by larger currents, the service life of the switching power supply 2 is prolonged, and the load is prevented from being damaged. It will be appreciated that the controller 13 may convert the first voltage into a first current and compare the first current with a preset output current, so as to achieve the purpose of overcurrent detection.
The resistance value of the first detection resistor R1 may be greater than or equal to 0.001 Ω and less than or equal to 1Ω, and in practical application, the resistance value of the first detection resistor R1 may be selected according to requirements. In a specific embodiment, the resistance of the first detection resistor R1 may be 0.002 Ω, so that the resistance of the first detection resistor R1 is smaller, and the detection efficiency of the overcurrent detection circuit 11 may be improved. The preset voltage can be selected according to actual application requirements, and in the embodiment of the utility model, the preset voltage is not particularly limited. The first switching element Q1 may be at least one of an electromagnetic relay, a triode (BJT, bipolar Junction Transistor), and a field-effect transistor (MOS transistor).
Referring to fig. 2 and 3, the first switching element Q1 may be an NMOS (N-Metal-Oxide-Semiconductor) transistor, wherein a drain D of the NMOS transistor is an input terminal of the first switching element Q1, a source S of the NMOS transistor is an output terminal of the first switching element Q1, and a gate G of the NMOS transistor is a controlled terminal of the first switching element Q1. When the controller 13 sends a low level signal to the gate G of the NMOS transistor, the drain D and the source S of the NMOS transistor are turned off, so that the overcurrent detection circuit 11 is turned off. When the controller 13 sends a high-level signal to the gate G of the NMOS tube, the drain D and the source S of the NMOS tube are conducted, so that the overcurrent detection circuit 11 is conducted, when the switch power supply 2 outputs a larger current to a load, the overcurrent detection circuit 11 can be used for detecting the larger current to prevent the larger current from burning out other electronic components or loads in the switch power supply 2, and therefore protection can be provided for the other electronic components in the current detection circuit 1, the service life of the switch power supply 2 is prolonged, and the load is ensured not to be damaged.
In other embodiments, the first switching element Q1 may be in other forms, for example, the first switching element Q1 may be interconnected by a plurality of electromagnetic relays, to implement on and off control over the overcurrent detecting circuit 11, the first switching element Q1 may be interconnected by a plurality of transistors, to implement on and off control over the overcurrent detecting circuit 11, and the first switching element Q1 may be interconnected by a plurality of field effect transistors, to implement on and off control over the overcurrent detecting circuit 11, which is not illustrated herein. In the embodiment of the present utility model, the specific form of the first switching element Q1 is not limited, and on and off control may be performed on the overcurrent detection circuit 11.
Referring to fig. 3, in a specific embodiment, the overcurrent detecting circuit 11 further includes a first current limiting resistor X1, the first reference node 11A is connected to the controller 13 through the first current limiting resistor X1, and the excessive current entering the controller 13 can be avoided by using the first current limiting resistor X1, so that the controller 13 can be protected, the controller 13 can be prevented from being burnt out, and the service life of the controller 13 can be further prolonged.
Referring to fig. 2 and 3, in a specific embodiment, the light load detection circuit 12 includes a second switching element Q2 and a second detection resistor R2, an input end of the second switching element Q2 is connected to the output port 23, and a controlled end of the second switching element Q2 is connected to the controller 13; the first end of the second detection resistor R2 is connected to the output end of the second switching element Q2 through the second reference node 12A, the second end of the second detection resistor R2 is grounded, and the second reference node 12A is connected to the controller 13.
When the switching power supply 2 is in the sleep state, the controller 13 transmits a third control signal to the controlled terminal of the second switching element Q2 to turn off between the input terminal and the output terminal of the second switching element Q2, so that the power consumption can be reduced. When the switching power supply 2 supplies power to a load, if the first voltage acquired by the controller 13 at the first reference node 11A is smaller than a preset voltage, the controller 13 sends a fourth control signal to the controlled end of the second switching element Q2 to enable conduction between the input end and the output end of the second switching element Q2, so that the output port 23 is grounded through the second switching element Q2 and the second detection resistor R2, so that the controller 13 can detect the second voltage at the second reference node 12A, and when the second voltage is smaller than the preset voltage, the controller 13 controls the light load detection circuit 12 to be kept on and controls the over-current detection circuit 11 to be kept off, so that the controller 13 can continuously acquire the second voltage from the second reference node 12A, and further light load detection is performed, thereby realizing detection of light load current by a simple circuit, reducing research and development cost, and reducing overall cost of the over-current detection circuit 11 and the light load detection circuit 12 due to the low cost of the whole detection circuit 1; secondly, the overcurrent detection circuit 11 and the light load detection circuit 12 are simpler, so that the product volume can be reduced, and the product is more miniaturized; more importantly, the overcurrent detection circuit 11 and the light load detection circuit 12 are simpler, so that the control logic of the current detection circuit 1 is simple, and the reliability of the current detection circuit 1 is improved, so that the reliability of a product is improved. It is understood that the controller 13 may convert the second voltage into the second current, and compare the second current with the preset output current, which is not described herein again.
The resistance value of the second detection resistor R2 may be greater than or equal to 0.05 Ω and less than or equal to 1Ω, in specific use, may be selected according to requirements, and the resistance value of the second detection resistor R2 is greater than the resistance value of the first detection resistor R1, specifically, the difference between the resistance value of the first detection resistor R1 and the resistance value of the second detection resistor R2 is greater than or equal to 0.005 Ω and less than or equal to 0.5Ω, so that under the condition that the current is the same, the second voltage at the second reference node 12A is greater than the first voltage at the first reference node 11A, thereby being convenient for the controller 13 to detect the light load current. The second switching element Q2 may be at least one of an electromagnetic relay, a triode, and a field effect transistor.
Referring to fig. 2 and 3, the second switching element Q2 may be an NMOS transistor, where a drain D of the NMOS transistor is an input end of the second switching element Q2, a source S of the NMOS transistor is an output end of the second switching element Q2, and a gate G of the NMOS transistor is a controlled end of the second switching element Q2. When the controller 13 sends a low-level signal to the gate G of the NMOS transistor, the drain D and the source S of the NMOS transistor are turned off, so that the light load detection circuit 12 is turned off to reduce power consumption. When the controller 13 sends a high-level signal to the gate G of the NMOS tube, the drain D and the source S of the NMOS tube are conducted, so that the light load detection circuit 12 is conducted, and when the switching power supply 2 is connected to a smaller load and generates a smaller current, the light load detection circuit 12 can be used for detecting the light load current of the smaller current.
In other embodiments, the second switching element Q2 may be in other forms, for example, the second switching element Q2 may be connected to each other by a plurality of electromagnetic relays to perform on and off control of the light load detection circuit 12; the second switching element Q2 may be further connected to each other by a plurality of transistors to perform on/off control of the light load detection circuit 12; the second switching element Q2 may be further connected to each other by a plurality of field effect transistors to perform on and off control of the light load detection circuit 12, which is exemplified herein. In the embodiment of the present utility model, the specific form of the second switching element Q2 is not limited, and the on and off control of the light load detection circuit 12 may be performed.
Referring to fig. 3, in a specific embodiment, the light load detection circuit 12 includes a second current limiting resistor X2, the second reference node 12A is connected to the controller 13 through the second current limiting resistor X2, and the second current limiting resistor X2 can prevent the excessive current entering the controller 13, so as to protect the controller 13 from being burnt out, and further prolong the service life of the controller 13.
In the embodiment of the present utility model, when the switching power supply 2 supplies power to the load through the output port 23, compared with the preferential conduction light load detection circuit 12, the preferential conduction overcurrent detection circuit 11 can utilize the first detection resistor R1 with a resistance smaller than the second detection resistor R2 when the power supply current is larger, so that the first voltage at the first reference node 11A is smaller than the second voltage at the second reference node 12A, thereby preventing the controller 13 from being burned out and prolonging the service life of the controller 13.
In a second aspect, referring to fig. 2 and 3, an embodiment of the present utility model further provides a switching power supply 2, which includes a housing 21, a circuit board 22 and a current detection circuit 1, wherein the circuit board 22 is disposed in the housing 21, and the current detection circuit 1 is disposed on the circuit board 22, so that an output current of the switching power supply 2 can be detected by the current detection circuit 1. Wherein, the casing 21 may be made of an insulating material, such as plastic, to prevent the switch power supply 2 from leaking electricity, so as to ensure the use safety of the user, and the casing 21 made of the plastic material has a light weight, so that the switch power supply 2 has a light weight, thereby facilitating the movement of the switch power supply 2. The current detection circuit 1 may be formed on the circuit board 22 by an etching process and electrically connected to the output port 23 of the switching power supply 2, so that the current detection circuit 1 detects the output current of the switching power supply 2.
The switch power supply 2 may be a mobile power supply, the output port 23 is electrically connected with a built-in battery of the mobile power supply, and the sleep state of the switch power supply 2 corresponds to the sleep state of the mobile power supply, so that the electric energy loss of the built-in battery can be reduced, and when the mobile power supply supplies power to a load, the controller 13 controls the current detection circuit 1 to detect the output current of the output port 23. Specifically, when the mobile power supply supplies power to the load, the controller 13 can control the over-current detection circuit 11 to be turned on, so as to provide over-current detection for the mobile power supply; when the load is fully charged, the controller 13 can control the light load detection circuit 12 to be conducted so as to provide light load detection for the mobile power supply; the load leaves the output port 23, and after a preset time, the controller 13 can control the mobile power supply to enter a sleep state according to the program setting, so as to further reduce the power consumption of the mobile power supply.
In other embodiments, the switching power supply 2 may also be a charger, and the current detection circuit 1 is also connected to the output port 23, so that the output current of the output port 23 may be detected by using the current detection circuit 1 to protect a charging device electrically connected to the output port 23.
The output port 23 may be ase:Sub>A USB (Universal Serial Bus ) interface, such as ase:Sub>A Micro-USB interface, ase:Sub>A USB-ase:Sub>A interface, and ase:Sub>A USB Type-C interface. In other embodiments, the output port 23 may also be in other forms, such as a lighting interface. In the embodiment of the present utility model, the specific form of the output port 23 is not limited.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present utility model, it should be understood that, if there is an azimuth or positional relationship indicated by terms such as "upper", "lower", "left", "right", etc., based on the azimuth or positional relationship shown in the drawings, it is only for convenience of describing the present utility model and simplifying the description, but it is not indicated or implied that the apparatus or element referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and thus terms describing the positional relationship in the drawings are merely illustrative and should not be construed as limitations of the present patent, and specific meanings of the terms described above may be understood by those skilled in the art according to specific circumstances.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.
Claims (10)
1. A current detection circuit of a switching power supply, comprising:
the overcurrent detection circuit is connected with an output port of the switching power supply and provided with a first reference node, and the first reference node is provided with a first voltage;
the light load detection circuit is connected with the overcurrent detection circuit in parallel, is connected with an output port of the switching power supply, and is provided with a second reference node, and the second reference node is provided with a second voltage;
the controller is connected with the overcurrent detection circuit and the light load detection circuit, acquires the first voltage or the second voltage, and controls the overcurrent detection circuit to be in a conducting state and controls the light load detection circuit to be in a cutting-off state when the first voltage is greater than or equal to a preset voltage so that the controller acquires the first voltage and carries out overcurrent detection on the output port; when the first voltage is smaller than the preset voltage, the controller controls the overcurrent detection circuit to be in an off state and controls the light load detection circuit to be in an on state, so that the controller obtains the second voltage and light load detection is carried out on the output port; when the second voltage is greater than or equal to the preset voltage, the controller controls the overcurrent detection circuit to be in a conducting state and controls the light load detection circuit to be in a cutting-off state, so that the controller obtains the first voltage and carries out overcurrent detection on the output port.
2. The current detection circuit of claim 1, wherein the over-current detection circuit comprises:
the input end of the first switching element is connected with the output port, and the controlled end of the first switching element is connected with the controller;
the first end of the first detection resistor is connected with the output end of the first switch element through the first reference node, the second end of the first detection resistor is grounded, and the first reference node is connected with the controller.
3. The current detection circuit of claim 2, wherein the over-current detection circuit further comprises:
the first reference node is connected with the controller through the first current limiting resistor.
4. The current detection circuit of claim 2, wherein the light load detection circuit comprises:
the input end of the second switching element is connected with the output port, and the controlled end of the second switching element is connected with the controller;
the first end of the second detection resistor is connected with the output end of the second switching element through the second reference node, the second end of the second detection resistor is grounded, and the second reference node is connected with the controller.
5. The current detection circuit of claim 4, wherein the light load detection circuit comprises:
and the second reference node is connected with the controller through the second current limiting resistor.
6. The current detection circuit according to claim 4, wherein a resistance value of the first detection resistor is 0.001 Ω or more and 1 Ω or less; and/or, the resistance value of the second detection resistor is greater than or equal to 0.05 Ω and less than or equal to 1 Ω.
7. The current detection circuit of claim 4, wherein a resistance value of the first detection resistor is smaller than a resistance value of the second detection resistor.
8. The current detecting circuit according to claim 7, wherein a difference between a resistance value of the first detecting resistor and a resistance value of the second detecting resistor is equal to or greater than 0.005 Ω and equal to or less than 0.5 Ω.
9. The current detection circuit of claim 4, wherein the first switching element and the second switching element are at least one of a relay, a triode, and a field effect transistor.
10. A switching power supply, comprising:
a housing;
the circuit board is arranged in the shell;
a current sensing circuit according to any one of claims 1 to 9, disposed on the circuit board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320709637.2U CN219740189U (en) | 2023-04-03 | 2023-04-03 | Current detection circuit of switching power supply and switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320709637.2U CN219740189U (en) | 2023-04-03 | 2023-04-03 | Current detection circuit of switching power supply and switching power supply |
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| Publication Number | Publication Date |
|---|---|
| CN219740189U true CN219740189U (en) | 2023-09-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320709637.2U Active CN219740189U (en) | 2023-04-03 | 2023-04-03 | Current detection circuit of switching power supply and switching power supply |
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| Country | Link |
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| CN (1) | CN219740189U (en) |
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